As a conventional power conversion device that converts DC power to DC power, a power conversion device has been proposed wherein two single-phase full-bridge circuits that include semiconductor switching elements and perform power conversion between DC power and AC power are used, and AC terminals of the respective single-phase full-bridge circuits are connected via a transformer. Accordingly, the primary side and the secondary side are insulated from each other, whereby a power conversion device capable of performing DC/DC conversion is implemented.
Alternatively, two three-phase bridge converters are used instead of the single-phase full-bridge circuits, and AC terminals of the respective three-phase bridge converters are connected via a three-phase transformer, whereby a power conversion device capable of performing DC/DC conversion is also implemented (see Patent Document 1, for example).
Further, as a conventional power conversion device using a plurality of insulation-type converters, a power conversion device including a plurality of power electronics modules which are substantially identical to one another, has been proposed. Each of the power electronics modules includes a single-phase DC/AC inverter with an output side and an insulation type DC/DC converter with an input side. The insulation type DC/DC converters are continuously connected to the corresponding single-phase DC/AC inverters so as to share DC link capacitors. In the structure in which the plurality of power electronics modules are connected in series, any malfunctioning module is bypassed with use of a bypass switch so that the remaining modules are operated (see Patent Document 2, for example).